Abstract: The invention relates to the production of organic field-effect transistors (OFETs), solar cells or light-emitting diodes (OLEDs) and circuits based thereon on the surface of solvent- and/or temperature-sensitive plastics, e.g. thermoplastic injection-moulded bodies. A protective layer, which comprises a polymer compound, such as polyacrylate, polyphenol, melamine resin or polyester resin, which is applied from an aqueous-alcoholic solution or without solvent to the substrate surface or one of the function-determining layers of the electronic semiconductor component in a low-temperature process at temperatures of less than 100° C. and dried, protects the substrate against undesirable action of solvents and may simultaneously serve as a planarization layer and/or as as electrical insulation layer.